diff --git a/pkgs/development/ocaml-modules/biniou/1.0.nix b/pkgs/development/ocaml-modules/biniou/1.0.nix
index 5a2e2ea9a7f..ec81e5b8db9 100644
--- a/pkgs/development/ocaml-modules/biniou/1.0.nix
+++ b/pkgs/development/ocaml-modules/biniou/1.0.nix
@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
   makeFlags = [ "PREFIX=$(out)" ];
 
   preBuild = ''
-    mkdir $out/bin
+    mkdir -p $out/bin
   '';
 
   meta = with lib; {